The fourth season of Demon Slayer is currently airing with the Hashira Training Arc. From the title alone, fans were able to guess that this season would heavily focus on the most powerful demon slayers, the Hashira, and were exactly right. The story has shifted to focus on the Hashira who still remain part of the Demon Slayer Corps as they try to get the regular cadets trained and prepared for the inevitable fight with Muzan, the leader of the demons.

But one thing has changed a lot about the Demon Slayer Corps this season, namely with the Hashira. The Hashira were always commanded by a mysterious man named Kagaya Ubuyashiki. From his first appearance in the anime back in Episode 5 (though we did not see him fully until Episode 22), it was obvious that something was wrong with him. The more screen time Kagaya got, the more obvious it became. In the Hashira Training Arc, though, Kagaya is so sick he can no longer lead the Demon Slayer Corps. But what exactly is wrong with him?

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The Markings on Kagaya Ubuyashiki's Skin

Despite being in actuality only 23 years old, Kagaya Ubuyashiki looks much older. This is due to the strange markings on his skin. When he was first introduced in Demon Slayer, the marks already covered most of his face, stretching from his forehead all the way across his nose. The markings are purple and have a rough, scaly appearance, and have blinded him. By the Hashira Training Arc, the marks have spread beyond just his forehead, over much of his face and onto the rest of his body. He can be seen bedridden because of his condition, and covered in bandages.

In flashbacks, though, Kagaya can be seen as a teenager before the markings took over so much of his face. This shows the original purple mark over just his right eye - a curse mark, born from the curse of a demon. While the curse mark starts off small, it grows as Kagaya ages, giving his skin a rotten appearance as it slowly spreads from his right eye to eventually cover his entire body. Eventually, the curse mark's power will kill him, and has already rendered him unable to move by the Hashira Training Arc, and thus unable to lead the Demon Slayer Corps any longer.

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The Ubuyashiki Family Curse

Kagaya Ubuyashiki's fate is no surprise to him, because it is a curse that all the men in his family have carried for generations. The Demon King, Muzan Kibutsuji, came from the Ubuyashiki family bloodline a millennium before the time of Demon Slayer. It is from Muzan that all other demons have come, and thus the Ubuyashiki family was cursed for bringing the first demon into the world. This curse is passed down genetically through the family in the form of a curse mark, causing all boys to die before the age of 30. Girls can only escape it by marrying by age 13 and changing their names.

Because of this, the Ubuyashiki family has been running the Demon Slayer Corps out of a sense of responsibility. It is also why Kagaya has worked so hard to train the Hashira into the incredible fighting force that they are. He knows that he will not be here for long, so he has to be strict with their training in the time that he has. Because he is now not only blind but bedridden, his partner Amane Ubuyashiki now speaks to the Hashira and the rest of the Demon Slayer Corps on his behalf. She is also Kagaya's primary caregiver, doing what she can to make him comfortable until the end.

Though he has been dying his whole life from the curse of the demons, Kagaya Ubuyashiki has accomplished a lot. He created the strongest force the Demon Slayer Corps have ever seen, with the Hashira, who have finally been able to stand up to even Muzan's most elite demon forces. He also accepted Tanjiro and Nezuko, despite Nezuko being a demon herself. His deep hatred for Muzan, despite being from the same bloodline, has driven him so far, and continues to motivate him and the work he began even on his deathbed.

Watch the latest season of Demon Slayer on Crunchyroll.

Demon Slayer

Based on Koyoharu Gotouge's shonen manga, Demon Slayer: Kimetsu no Yaiba is an action anime set in Japan during the early 20th century. Seeking revenge for the murder of his family while also looking to save his sister, Tanjiro joins the Demon Slayer Corps as they try to eradicate Demons led by Muzan.